It is known to provide a protective coating on a substrate to protect the substrate during processing, or handling or shipping. Such protective coatings are used on a variety of substrate materials. In many instances, the protective coatings can be stripped from the underlying substrate material without affecting the surface characteristics of the underlying material.
An example of one such material is setforth in U.S. Pat. No. 3,491,039 wherein the coating is suggested for use in protecting a variety of products and materials including materials having decorative features thereon. While suitable for its intended purpose, there is no suggestion of utilizing the coating in a thermoforming process which will protect either thermally sensitive carrier films or thermally sensitive decorative features on such carrier film.
It is also known to provide a protective coating on wall cover and headliner materials for use in motor vehicles. The protective coating is applied to such materials as they are being processed and handled by employees in a plant environment. Such protective coatings are known to include a film which is laminated on a part by thermoforming. In such case the protective coating is formed from a material which will stretch and withstand deep drawing against the substrate material. An example of such prior art is U.S. Pat. No. 4,623,413 which discloses a protective film of unoriented polypropylene.
It is also known to provide a protective coating on relatively rigid components of a vehicle such as is shown in U.S. Pat. No. 4,477,504 wherein a polymer film is vacuum formed to cover a instrument panel insert during its processing to form a cellular foam product.
The aforesaid methods do not disclose a process to protect a thermaly limited carrier film during thermoforming thereof against a relatively rigid substrate. In particular, the known processes or methods fail to disclose steps for solving the problem of thermal degradation of heat sensitive carrier films and/or heat sensitive decorative features thereon.